The Babel Fish is small, yellow, leech-like, and is a universal translator which simultaneously translates from one spoken language to another. When inserted into the ear, its nutrition processes convert sound waves into brain waves, neatly crossing the language divide between any species you should happen to meet whilst travelling in space. Meanwhile, the poor Babel fish, by effectively removing all barriers to communication between different races and cultures, has caused more and bloodier wars than anything else in the history of creation. Arthur Dent, a surviving Earthling, commented only 'Eurgh!' when first inserting the fish into his ear canal. It did, however, enable him to understand Vogon Poetry - not necessarily a good thing. The book points out that the Babel Fish could not possibly have developed naturally, and therefore proves the existence of God as its creator. However, as Man points out, God needs faith to exist, and this proof dispels the need for faith, therefore causing God to vanish "in a puff of logic".